| 100% | EQUINOX | 7 | When day and night are approximately the same duration |
| 53% | EQUINOX | 7 | When day and night are of equal length |
| 51% | EQUINOX | 7 | Either of the two occasions when day and night are of equal length |
| 51% | EQUINOX | 7 | Time when day and night are of equal length |
| 51% | EQUINOX | 7 | Period when day and night are of equal length |
| 51% | EQUINOX | 7 | Date each year when day and night are equal length |
| 43% | EQUINOX | 7 | Time when night and day are equally long |
| 41% | NOON | 4 | Time of the day when the sun is fully up and about |
| 40% | TWILIGHT | 8 | Period when day is ending and night is beginning |
| 39% | DARWIN | 6 | He and Lincoln were born on the exact same day: February 12, 1809 |
| 38% | FLOOD | 5 | Event lasting 40 days and nights in the Bible |
| 37% | SOLSTICE | 8 | *Winter ___, annual cosmic event when the day is shortest...and a connecting theme for 31a, 39a, 42a, 8d, and 20d |
| 37% | ONEMORE | 7 | "___ Time," 2023 movie about a person stuck in the same day ... which is also a hint for 18a, 30a, 35a, 4d, and 39d: 2 wds. |
| 36% | TWILIGHT | 8 | The period between day and night |
| 36% | FORTY | 5 | Number of days and nights of rainfall during the Bible's great flood |
| 35% | STANDBYME | 9 | King classic that begins, "When the night has come / And the land is dark" |
| 35% | ACED | 4 | After studying day and night regularly he was sure that he had ___ his exam |
| 35% | LEAVEITTOBEAVER | 15 | This and Sputnik 1 were launched on the same day |
| 35% | GAMETHEORY | 10 | "Hares and rabbits are really the same animal, some say" |
| 35% | THU | 3 | Day when the Last Supper is commemorated: Abbr. |
| 35% | CRAMS | 5 | Hits the books day and night |
| 35% | UPRISE | 6 | Revolt, and when its two syllables are swapped, a phrase meaning the same thing |
| 35% | YOU | 3 | Word pronounced the same when its first two letters are removed |
| 35% | ATNIGHT | 7 | When Santa and the tooth fairy are most active |
| 35% | APR | 3 | When Arbor Day is celebrated in the US: Abbr. |
| 35% | TUE | 3 | Day of the week when Mardi Gras is: Abbr. |
| 35% | TOMORROW | 8 | The day that is always coming and never arrives |
| 34% | KEY | 3 | 1 and ! are on the same one on a typewriter |
| 34% | EQUINOX | 7 | Twice-yearly time when day, night are nearly equal |
| 34% | TUESDAY | 7 | Day of the week when the Melbourne Cup is run |